Substituted pyrazolo[1,5-a]pyrimidines as protein kinase inhibitors

ABSTRACT

In its many embodiments, the present invention provides a class of pyrazolo[1,5-a]pyrimidine compounds as inhibitors of cyclin dependent kinases (CDKs), methods of preparing such compounds, pharmaceutical compositions containing one or more such compounds, methods of preparing pharmaceutical formulations comprising one or more such compounds, and methods of treatment, prevention, inhibition, or amelioration of one or more diseases associated with the CDKs using such compounds or pharmaceutical compositions. An illustrative compound of the invention is shown below:

REFERENCE TO PRIORITY APPLICATIONS

This application is a Continuation-in-Part of U.S. patent application Ser. No. 11/244,772 filed Oct. 6, 2005 (which published as US 2006/0041131 on Feb. 23, 2006), which is a Continuation-in-Part of U.S. application Ser. No. 10/653,776 filed Sep. 3, 2003 (which published as US 2004/0106624), which claims the benefit of priority from U.S. Provisional Patent Application Ser. No. 60/408,029, filed on Sep. 4, 2002.

FIELD OF THE INVENTION

The present invention relates to pyrazolo[1,5-a]pyrimidine compounds useful as protein kinase inhibitors, pharmaceutical compositions containing the compounds, and methods of treatment using the compounds and compositions to treat diseases such as, for example, cancer, inflammation, arthritis, viral diseases, neurodegenerative diseases such as Alzheimer's disease, cardiovascular diseases, and fungal diseases. This application claims benefit of priority from U.S. provisional patent application Ser. No. 60/408,029 filed Sep. 4, 2002.

BACKGROUND OF THE INVENTION

The cyclin-dependent kinases (CDKs) are serine/threonine protein kinases, which are the driving force behind the cell cycle and cell proliferation. Individual CDK's, such as, CDK1, CDK2, CDK3, CDK4, CDK5, CDK6 and CDK7, CDK8 and the like, perform distinct roles in cell cycle progression and can be classified as either G1, S, or G2M phase enzymes. Uncontrolled proliferation is a hallmark of cancer cells, and misregulation of CDK function occurs with high frequency in many important solid tumors. CDK2 and CDK4 are of particular interest because their activities are frequently misregulated in a wide variety of human cancers. CDK2 activity is required for progression through G1 to the S phase of the cell cycle, and CDK2 is one of the key components of the G1 checkpoint. Checkpoints serve to maintain the proper sequence of cell cycle events and allow the cell to respond to insults or to proliferative signals, while the loss of proper checkpoint control in cancer cells contributes to tumorgenesis. The CDK2 pathway influences tumorgenesis at the level of tumor suppressor function (e.g. p52, RB, and p27) and oncogene activation (cyclin E). Many reports have demonstrated that both the coactivator, cyclin E, and the inhibitor, p27, of CDK2 are either over—or underexpressed, respectively, in breast, colon, nonsmall cell lung, gastric, prostate, bladder, non-Hodgkin's lymphoma, ovarian, and other cancers. Their altered expression has been shown to correlate with increased CDK2 activity levels and poor overall survival. This observation makes CDK2 and its regulatory pathways compelling targets for the development years, a number of adenosine 5′-triphosphate (ATP) competitive small organic molecules as well as peptides have been reported in the literature as CDK inhibitors for the potential treatment of cancers. U.S. Pat. No. 6,413,974, col. 1, line 23- col. 15, line 10 offers a good description of the various CDKs and their relationship to various types of cancer.

CDK inhibitors are known. For example, flavopiridol (Formula I) is a nonselective CDK inhibitor that is currently undergoing human clinical trials, A. M. Sanderowicz et al, J. Clin. Oncol. (1998) 16, 2986-2999.

Other known inhibitors of the CDKs include, for example, olomoucine (J. Vesely et al, Eur. J. Biochem., (1994) 224, 771-786) and roscovitine (I. Meijer et 20 al, Eur. J. Biochem., (1997) 243, 527-536). U.S. Pat. No. 6,107,305 describes certain pyrazolo[3,4-b]pyridine compounds as CDK inhibitors. An illustrative compound from the '305 patent has the Formula II:

K. S. Kim et al, J. Med. Chem. 45 (2002) 3905-3927 and WO 02/10162 disclose certain aminothiazole compounds as CDK inhibitors.

Pyrazolopyrimidines are known. For Example, WO92/18504, WO02/50079, WO95/35298, WO02/40485, EP94304104.6, EP0628559 (equivalent to U.S. Pat. Nos. 5,602,136, 5,602,137 and 5,571,813), U.S. Pat. No. 6,383,790, Chem. Pharm. Bull., (1999) 47 928, J. Med. Chem., (1977) 20, 296, J. Med. Chem., (1976) 19 517 and Chem. Pharm. Bull., (1962) 10 620 disclose various pyrazolopyrimidines. The string of parent cases for this present application, U.S. patent application Ser. No. 11/244,772 filed Oct. 6, 2005 (which published as US 2006/0041131 on Feb. 23, 2006), and U.S. application Ser. No. 10/653,776 filed Sep. 3, 2003 (which published as US 2004/0106624) should be considered as part of this invention.

There is a need for new compounds, formulations, treatments and therapies to treat diseases and disorders associated with CDKs. It is, therefore, an object of this invention to provide compounds useful in the treatment or prevention or amelioration of such diseases and disorders.

SUMMARY OF THE INVENTION

In its many embodiments, the afore-mentioned U.S. patent application Ser. No. 11/244,772 filed Oct. 6, 2005 (which published as US 2006/0041131 on Feb. 23, 2006) provides a novel class of pyrazolo[1,5-a]pyrimidine compounds as inhibitors of cyclin dependent kinases, methods of preparing such compounds, pharmaceutical compositions comprising one or more such compounds, methods of preparing pharmaceutical formulations comprising one or more such compounds, and methods of treatment, prevention, inhibition or amelioration of one or more diseases associated with the CDKs using such compounds or pharmaceutical compositions.

In one aspect, the afore-mentioned U.S. patent application Ser. No. 11/244,772 discloses a compound, or pharmaceutically acceptable salts, solvates, esters or prodrugs of said compound, said compound having the general structure shown in Formula III:

or a pharmaceutically acceptable salt, solvate, ester or prodrug of said compound, wherein:

R is an aryl, wherein said aryl is either unsubstituted or optionally substituted or fused with one or more heteroaryl;

R² is selected from the group consisting of R⁹, alkyl, alkynyl, alkynylalkyl, cycloalkyl, —CF₃, —C(O₂)R⁶, aryl, arylalkyl, heteroarylalkyl, heterocyclyl, alkyl substituted with 1-6 R⁹ groups which groups can be the same or different with each R⁹ being independently selected, aryl substituted with 1-3 aryl or heteroaryl groups which can be the same or different and are independently selected from phenyl, pyridyl, thiophenyl, furanyl and thiazolo groups,

heteroaryl substituted with 0-3 aryl or heteroaryl groups which can be the same or different and are independently selected from alkyl, phenyl, pyridyl, thiophenyl, furanyl and thiazolo groups;

R³ is selected from the group consisting of H, halogen, —NR⁵R⁶, —C(O)NR⁵R⁶, alkyl, alkynyl, cycloalkyl, aryl, arylalkyl, heterocyclyl, heterocyclylalkyl, heteroaryl and heteroarylalkyl,

wherein each of said alkyl, cycloalkyl, aryl, arylalkyl, heterocyclyl, heterocyclylalkyl, heteroaryl and heteroarylalkyl for R³ and the heterocyclyl moieties whose structures are shown immediately above for R³ can be substituted or optionally independently substituted with one or more moieties which can be the same or different, each moiety being independently selected from the group consisting of halogen, alkyl, aryl, cycloalkyl, CF₃, CN, —OCF₃, —(CR⁴R⁵)_(n)OR⁵, —OR⁵, —NR⁵R⁶, —(CR⁴R⁵)_(n)NR⁵R⁶, —C(O₂)R⁵, —C(O)R⁵, —C(O)NR⁵R⁶, —SR⁶, —S(O₂)R⁶, —S(O₂)NR⁵R⁶, —N(R⁵)S(O₂)R⁷, —N(R⁵)C(O)R⁷ and —N(R⁵)C(O)NR⁵R⁶;

R⁴ is H, halo or alkyl;

R⁵ is H or alkyl;

R⁶ is selected from the group consisting of H, alkyl, aryl, arylalkyl, cycloalkyl, heterocyclyl, heterocyclylalkyl, heteroaryl, and heteroarylalkyl, wherein each of said alkyl, aryl, arylalkyl, cycloalkyl, heterocyclyl, heterocyclylalkyl, heteroaryl, and heteroarylalkyl can be unsubstituted or optionally substituted with one or more moieties which can be the same or different, each moiety being independently selected from the group consisting of halogen, alkyl, aryl, cycloalkyl, heterocyclylalkyl, CF₃, OCF₃, CN, —OR⁵, —NR⁵R¹⁰, —N(R⁵)Boc, —(CR⁴R⁵)_(n)OR⁵, —C(O₂)R⁵, —C(O)R⁵, —C(O)NR⁵R¹⁰, —SO₃H, —SR¹⁰, —S(O₂)R⁷, —S(O₂)NR⁵R¹⁰, —N(R⁵)S(O₂)R⁷, —N(R⁵)C(O)R⁷ and —N(R⁵)C(O)NR⁵R¹⁰;

R¹⁰ is selected from the group consisting of H, alkyl, aryl, arylalkyl, cycloalkyl, heterocyclyl, heterocyclylalkyl, heteroaryl, and heteroarylalkyl, wherein each of said alkyl, aryl, arylalkyl, cycloalkyl, heterocyclyl, heterocyclylalkyl, heteroaryl, and heteroarylalkyl can be unsubstituted or optionally substituted with one or more moieties which can be the same or different, each moiety being independently selected from the group consisting of halogen, alkyl, aryl, cycloalkyl, heterocyclylalkyl, CF₃, OCF₃, CN, —OR⁵, —NR⁴R⁵, —N(R⁵)Boc, —(CR⁴R⁵)_(n)OR⁵, —C(O₂)R⁵, —C(O)NR⁴R⁵, —C(O)R⁵, —SO₃H, —SR⁵, —S(O₂)R⁷, —S(O₂)NR⁴R⁵, —N(R⁵)S(O₂)R⁷, —N(R⁵)C(O)R⁷ and —N(R⁵)C(O)NR⁴R⁵;

-   -   or optionally (i) R⁵ and R¹⁰ in the moiety —NR⁵R¹⁰, or (ii) R⁵         and R⁶ in the moiety —NR⁵R⁶, may be joined together to form a         cycloalkyl or heterocyclyl moiety, with each of said cycloalkyl         or heterocyclyl moiety being unsubstituted or optionally         independently being substituted with one or more R⁹ groups;

R⁷ is selected from the group consisting of alkyl, cycloalkyl, aryl, heteroaryl, arylalkyl and heteroarylalkyl, wherein each of said alkyl, cycloalkyl, heteroarylalkyl, aryl, heteroaryl and arylalkyl can be unsubstituted or optionally independently substituted with one or more moieties which can be the same or different, each moiety being independently selected from the group consisting of halogen, alkyl, aryl, cycloalkyl, CF₃, OCF₃, CN, —OR⁵, —NR⁵R¹⁰, —CH₂OR⁵, —C(O₂)R⁵, —C(O)NR⁵R¹⁰, —C(O)R⁵, —SR¹⁰, —S(O₂)R¹⁰, —S(O₂)NR⁵R¹⁰, —N(R⁵)S(O₂)R¹⁰, —N(R⁵)C(O)R¹⁰ and —N(R⁵)C(O)NR⁵R¹⁰;

R⁸ is selected from the group consisting of R⁶, —C(O)NR⁵R¹⁰, —S(O₂)NR⁵R¹⁰, —C(O)R⁷ and —S(O₂)R⁷;

R⁹ is selected from the group consisting of halogen, CN, —NR⁵R¹⁰, —C(O₂)R⁶, —C(O)NR⁵R¹⁰, —OR⁶, —SR⁶, —S(O₂)R⁷, —S(O₂)NR⁵R¹⁰, —N(R⁵)S(O₂)R⁷, —N(R⁵)C(O)R⁷and —N(R⁵)C(O)NR⁵R¹⁰;

m is 0 to 4, and

n is 1 to 4,

with the following provisos: (i) that when R is an unsubstituted phenyl, then R² is not alkyl, —C(O₂)R⁶, aryl or cycloalkyl, and (ii) that when R is a phenyl substituted with a hydroxyl group, then R² is halogen only.

The present invention discloses the compounds shown in Table 1, or a pharmaceutically acceptable salt, solvate, ester or prodrug thereof.

The compounds of the present invention can be useful as protein kinase inhibitors and can be useful in the treatment and prevention of proliferative diseases, for example, cancer, inflammation and arthritis. They may also be useful in the treatment of neurodegenerative diseases such Alzheimer's disease, cardiovascular diseases, viral diseases and fungal diseases.

DETAILED DESCRIPTION

In one embodiment, the present invention discloses pyrazolo[1,5-a]pyrimidine compounds, or a pharmaceutically acceptable salt, solvate, ester or prodrug thereof.

In another embodiment, this invention discloses the inventive compounds shown in Table 1 as well as a pharmaceutically acceptable salt, solvate, ester or prodrug thereof.

TABLE 1

As used above, and throughout this disclosure, the terms for the various moieties herein are understood to have the meanings defined in the afore-mentioned US2006/0041131, and especially on page 14, paragraph [0055] through page 18, paragraph [0101] therein, both inclusive.

Prodrugs and solvates of the compounds of the invention are also contemplated herein. A discussion of prodrugs is provided in T. Higuchi and V. Stella, Pro-drugs as Novel Delivery Systems (1987) 14 of the A.C.S. Symposium Series, and in Bioreversible Carriers in Drug Design, (1987) Edward B. Roche, ed., American Pharmaceutical Association and Pergamon Press. The term “prodrug” means a compound (e.g, a drug precursor) that is transformed in vivo to yield a compound of The invention or a pharmaceutically acceptable salt, hydrate or solvate of the compound. The transformation may occur by various mechanisms (e.g., by metabolic or chemical processes), such as, for example, through hydrolysis in blood. A discussion of the use of prodrugs is provided by T. Higuchi and W. Stella, “Pro-drugs as Novel Delivery Systems,” Vol. 14 of the A.C.S. Symposium Series, and in Bioreversible Carriers in Drug Design, ed. Edward B. Roche, American Pharmaceutical Association and Pergamon Press, 1987.

For example, if a compound of the invention or a pharmaceutically acceptable salt, hydrate or solvate of the compound contains a carboxylic acid functional group, a prodrug can comprise an ester formed by the replacement of the hydrogen atom of the acid group with a group such as, for example, (C₁-C₈)alkyl, (C₂-C₁₂)alkanoyloxymethyl, 1-(alkanoyloxy)ethyl having from 4 to 9 carbon atoms, 1-methyl-1-(alkanoyloxy)-ethyl having from 5 to 10 carbon atoms, alkoxycarbonyloxymethyl having from 3 to 6 carbon atoms, 1-(alkoxycarbonyloxy)ethyl having from 4 to 7 carbon atoms, 1-methyl-1-(alkoxycarbonyloxy)ethyl having from 5 to 8 carbon atoms, N-(alkoxycarbonyl)aminomethyl having from 3 to 9 carbon atoms, 1-(N-(alkoxycarbonyl)amino)ethyl having from 4 to 10 carbon atoms, 3-phthalidyl, 4-crotonolactonyl, gamma-butyrolacton-4-yl, di-N, N-(C₁-C₂)al kylamino(C₂-C₃)alkyl (such as β-dimethylaminoethyl), carbamoyl-(C₁-C₂)alkyl, N,N-di (C₁-C₂)alkylcarbamoyl-(C1-C2)alkyl and piperidino-, pyrrolidino- or morpholino(C₂-C₃)alkyl, and the like.

Similarly, if a compound of the invention contains an alcohol functional group, a prodrug can be formed by the replacement of the hydrogen atom of the alcohol group with a group such as, for example, (C₁-C₆)alkanoyloxymethyl, 1-((C₁-C₆)alkanoyloxy)ethyl, 1-methyl-1-((C₁-C₆)alkanoyloxy)ethyl, (C₁-C₆)alkoxycarbonyloxymethyl, N-(C₁-C₆)alkoxycarbonylaminomethyl, succinoyl, (C₁-C₆)alkanoyl, α-amino(C₁-C₄)alkanyl, arylacyl and α-aminoacyl, or α-aminoacyl-α-aminoacyl, where each α-aminoacyl group is independently selected from the naturally occurring L-amino acids, P(O)(OH)₂, —P(O)(O(C₁-C₆)alkyl)₂ or glycosyl (the radical resulting from the removal of a hydroxyl group of the hemiacetal form of a carbohydrate), and the like.

If a compound of the invention incorporates an amine functional group, a prodrug can be formed by the replacement of a hydrogen atom in the amine group with a group such as, for example, R-carbonyl, RO-carbonyl, NRR′-carbonyl where R and R′ are each independently (C₁-C₁₀)alkyl, (C₃-C₇) cycloalkyl, benzyl, or R-carbonyl is a natural a-aminoacyl or natural a-aminoacyl, —C(OH)C(O)OY¹ wherein Y¹ is H, (C₁-C₆)alkyl or benzyl, —C(OY²)Y³ wherein Y² is (C₁-C₄) alkyl and Y³ is (C₁-C₆)alkyl, carboxy (C₁-C₆)alkyl, amino(C₁-C₄)alkyl or mono-N-or di-N,N-(C₁-C₆)alkylaminoalkyl, —C(Y⁴)Y⁵ wherein Y⁴ is H or methyl and Y⁵ is mono-N-or di-N,N-(C₁-C₆)alkylamino morpholino, piperidin-1-yl or pyrrolidin-1-yl, and the like.

One or more compounds of the invention may exist in unsolvated as well as solvated forms with pharmaceutically acceptable solvents such as water, ethanol, and the like, and it is intended that the invention embrace both solvated and unsolvated forms. “Solvate” means a physical association of a compound of this invention with one or more solvent molecules. This physical association involves varying degrees of ionic and covalent bonding, including hydrogen bonding. In certain instances the solvate will be capable of isolation, for example when one or more solvent molecules are incorporated in the crystal lattice of the crystalline solid. “Solvate” encompasses both solution-phase and isolatable solvates. Non-limiting examples of suitable solvates include ethanolates, methanolates, and the like. “Hydrate” is a solvate wherein the solvent molecule is H₂O.

One or more compounds of the invention may optionally be converted to a solvate. Preparation of solvates is generally known. Thus, for example, M. Caira et al, J. Pharmaceutical Sci., 93(3), 601-611 (2004) describe the preparation of the solvates of the antifungal fluconazole in ethyl acetate as well as from water. Similar preparations of solvates, hemisolvate, hydrates and the like are described by E. C. van Tonder et al, AAPS PharmSciTech., 5(1), article 12 (2004); and A. L. Bingham et al, Chem. Commun., 603-604 (2001). A typical, non-limiting, process involves dissolving the inventive compound in desired amounts of the desired solvent (organic or water or mixtures thereof) at a higher than ambient temperature, and cooling the solution at a rate sufficient to form crystals which are then isolated by standard methods. Analytical techniques such as, for example I. R. spectroscopy, show the presence of the solvent (or water) in the crystals as a solvate (or hydrate).

“Effective amount” or “therapeutically effective amount” is meant to describe an amount of compound or a composition of the present invention effective in inhibiting the above-noted diseases and thus producing the desired therapeutic, ameliorative, inhibitory or preventative effect.

The compounds of the invention can form salts which are also within the scope of this invention. Reference to a compound of the invention herein is understood to include reference to salts thereof, unless otherwise indicated. The term “salt(s)”, as employed herein, denotes acidic salts formed with inorganic and/or organic acids, as well as basic salts formed with inorganic and/or organic bases. In addition, when a compound of the invention contains both a basic moiety, such as, but not limited to a pyridine or imidazole, and an acidic moiety, such as, but not limited to a carboxylic acid, zwitterions (“inner salts”) may be formed and are included within the term “salt(s)” as used herein. Pharmaceutically acceptable (i.e., non-toxic, physiologically acceptable) salts are preferred, although other salts are also useful. Salts of the compounds of the invention may be formed, for example, by reacting a compound of The invention with an amount of acid or base, such as an equivalent amount, in a medium such as one in which the salt precipitates or in an aqueous medium followed by lyophilization.

Exemplary acid addition salts include acetates, ascorbates, benzoates, benzenesulfonates, bisulfates, borates, butyrates, citrates, camphorates, camphorsulfonates, fumarates, hydrochlorides, hydrobromides, hydroiodides, lactates, maleates, methanesulfonates, naphthalenesulfonates, nitrates, oxalates, phosphates, propionates, salicylates, succinates, sulfates, tartarates, thiocyanates, toluenesulfonates (also known as tosylates,) and the like. Additionally, acids which are generally considered suitable for the formation of pharmaceutically useful salts from basic pharmaceutical compounds are discussed, for example, by P. Stahl et al, Camille G. (eds.) Handbook of Pharmaceutical Salts. Properties, Selection and Use. (2002) Zurich: Wiley-VCH; S. Berge et al, Journal of Pharmaceutical Sciences (1977) 66(1) 1-19; P. Gould, Intemational J. of Pharmaceutics (1986) 33 201-217; Anderson et al, The Practice of Medicinal Chemistry (1996), Academic Press, New York; and in The Orange Book (Food & Drug Administration, Washington, D.C. on their website). These disclosures are incorporated herein by reference thereto.

Exemplary basic salts include ammonium salts, alkali metal salts such as sodium, lithium, and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, salts with organic bases (for example, organic amines) such as dicyclohexylamines, t-butyl amines, and salts with amino acids such as arginine, lysine and the like. Basic nitrogen-containing groups may be quarternized with agents such as lower alkyl halides (e.g. methyl, ethyl, and butyl chlorides, bromides and iodides), dialkyl sulfates (e.g. dimethyl, diethyl, and dibutyl sulfates), long chain halides (e.g. decyl, lauryl, and stearyl chlorides, bromides and iodides), aralkyl halides (e.g. benzyl and phenethyl bromides), and others.

All such acid salts and base salts are intended to be pharmaceutically acceptable salts within the scope of the invention and all acid and base salts are considered equivalent to the free forms of the corresponding compounds for purposes of the invention.

Pharmaceutically acceptable esters of the present compounds include the following groups: (1) carboxylic acid esters obtained by esterification of the hydroxy groups, in which the non-carbonyl moiety of the carboxylic acid portion of the ester grouping is selected from straight or branched chain alkyl (for example, acetyl, n-propyl, t-butyl, or n-butyl), alkoxyalkyl (for example, methoxymethyl), aralkyl (for example, benzyl), aryloxyalkyl (for example, phenoxymethyl), aryl (for example, phenyl optionally substituted with, for example, halogen, C₁₋₄alkyl, or C₁₋₄alkoxy or amino); (2) sulfonate esters, such as alkyl- or aralkylsulfonyl (for example, methanesulfonyl); (3) amino acid esters (for example, L-valyl or L-isoleucyl); (4) phosphonate esters and (5) mono-, di- or triphosphate esters. The phosphate esters may be further esterified by, for example, a C₁₋₂₀ alcohol or reactive derivative thereof, or by a 2,3-di (C₆₋₂₄)acyl glycerol.

The compounds of the invention, and salts, solvates, esters and prodrugs thereof, may exist in their tautomeric form (for example, as an amide or imino ether). All such tautomeric forms are contemplated herein as part of the present invention.

The compounds of the invention may contain asymmetric or chiral centers, and, therefore, exist in different stereoisomeric forms. It is intended that all stereoisomeric forms of the compounds of the invention as well as mixtures thereof, including racemic mixtures, form part of the present invention. In addition, the present invention embraces all geometric and positional isomers. For example, if a compound of the invention incorporates a double bond or a fused ring, both the cis- and trans-forms, as well as mixtures, are embraced within the scope of the invention.

Diastereomeric mixtures can be separated into their individual diastereomers on the basis of their physical chemical differences by methods well known to those skilled in the art, such as, for example, by chromatography and/or fractional crystallization. Enantiomers can be separated by converting the enantiomeric mixture into a diastereomeric mixture by reaction with an appropriate optically active compound (e.g., chiral auxiliary such as a chiral alcohol or Mosher's acid chloride), separating the diastereomers and converting (e.g., hydrolyzing) the individual diastereomers to the corresponding pure enantiomers. Also, some of the compounds of the invention may be atropisomers (e.g., substituted biaryls) and are considered as part of this invention. Enantiomers can also be separated by use of chiral HPLC column.

It is also possible that the compounds of the invention may exist in different tautomeric forms, and all such forms are embraced within the scope of the invention. Also, for example, all keto-enol and imine-enamine forms of the compounds are included in the invention.

All stereoisomers (for example, geometric isomers, optical isomers and the like) of the present compounds (including those of the salts, solvates, esters and prodrugs of the compounds as well as the salts, solvates and esters of the prodrugs), such as those which may exist due to asymmetric carbons on various substituents, including enantiomeric forms (which may exist even in the absence of asymmetric carbons), rotameric forms, atropisomers, and diastereomeric forms, are contemplated within the scope of this invention, as are positional isomers (such as, for example, 4-pyridyl and 3-pyridyl). (For example, if a compound of the invention incorporates a double bond or a fused ring, both the cis- and trans-forms, as well as mixtures, are embraced within the scope of the invention. Also, for example, all keto-enol and imine-enamine forms of the compounds are included in the invention.) Individual stereoisomers of the compounds of the invention may, for example, be substantially free of other isomers, or may be admixed, for example, as racemates or with all other, or other selected, stereoisomers. The chiral centers of the present invention can have the S or R configuration as defined by the IUPAC 1974 Recommendations. The use of the terms “salt”, “solvate”, “ester”, “prodrug” and the like, is intended to equally apply to the salt, solvate, ester and prodrug of enantiomers, stereoisomers, rotamers, tautomers, positional isomers, racemates or prodrugs of the inventive compounds.

Diastereomeric mixtures can be separated into their individual diastereomers on the basis of their physical chemical differences by methods well known to those skilled in the art, such as, for example, by chromatography and/or fractional crystallization. Enantiomers can be separated by converting the enantiomeric mixture into a diastereomeric mixture by reaction with an appropriate optically active compound (e.g., chiral auxiliary such as a chiral alcohol or Mosher's acid chloride), separating the diastereomers and converting (e.g., hydrolyzing) the individual diastereomers to the corresponding pure enantiomers. Also, some of the compounds of the invention may be atropisomers (e.g., substituted biaryls) and are considered as part of this invention. Enantiomers can also be separated, for example, by use of chiral HPLC column.

The present invention also embraces isotopically-labelled compounds of the present invention which are identical to those recited herein, but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number usually found in nature. Examples of isotopes that can be incorporated into compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorus, fluorine and chlorine, such as ²H, ³H, ¹³C, ¹⁴C, ¹⁵N, ¹⁸O, ¹⁷O, ³¹P, ³²P, ³⁵S, ¹⁸F, and ³⁶Cl, respectively.

Certain isotopically-labelled compounds of the invention (e.g., those labeled with ³H and ¹⁴C) are useful in compound and/or substrate tissue distribution assays. Tritiated (i.e., ³H) and carbon-14 (i.e., ¹⁴C) isotopes are particularly preferred for their ease of preparation and detectability. Further, substitution with heavier isotopes such as deuterium (i.e., ²H) may afford certain therapeutic advantages resulting from greater metabolic stability (e.g., increased in vivo half-life or reduced dosage requirements) and hence may be preferred in some circumstances. Isotopically labelled compounds of the invention can generally be prepared by following procedures analogous to those disclosed in the Schemes and/or in the Examples hereinbelow, by substituting an appropriate isotopically labelled reagent for a non-isotopically labelled reagent.

Polymorphic forms of the compounds of the invention, and of the salts, solvates, esters and prodrugs of the compounds of The invention, are intended to be included in the present invention.

The term “pharmaceutical composition” is also intended to encompass both the bulk composition and individual dosage units comprised of more than one (e.g., two) pharmaceutically active agents such as, for example, a compound of the present invention and an additional agent selected from the lists of the additional agents described herein, along with any pharmaceutically inactive excipients. The bulk composition and each individual dosage unit can contain fixed amounts of the afore-said “more than one pharmaceutically active agents”. The bulk composition is material that has not yet been formed into individual dosage units. An illustrative dosage unit is an oral dosage unit such as tablets, pills and the like. Similarly, the herein-described method of treating a patient by administering a pharmaceutical composition of the present invention is also intended to encompass the administration of the afore-said bulk composition and individual dosage units.

The compounds according to the invention have pharmacological properties; in particular, the compounds of The invention can be inhibitors of protein kinases such as, for example, the inhibitors of the cyclin-dependent kinases, mitogen-activated protein kinase (MAPK/ERK), glycogen synthase kinase 3(GSK3beta) and the like. The cyclin dependent kinases (CDKS) include, for example, CDC2 (CDK1), CDK2, CDK4, CDK5, CDK6, CDK7 CDK8 and CDK9. The novel compounds of The invention are expected to be useful in the therapy of proliferative diseases such as cancer, autoimmune diseases, viral diseases, fungal diseases, neurological/neurodegenerative disorders, arthritis, inflammation, anti-proliferative (e.g., ocular retinopathy), neuronal, alopecia and cardiovascular disease. Many of these diseases and disorders are listed in U.S. Pat. No. 6,413,974 cited earlier, the disclosure of which is incorporated herein.

More specifically, the compounds of the invention can be useful in the treatment of a variety of cancers, including (but not limited to) the following: carcinoma, including that of the bladder, breast, colon, kidney, liver, lung, including small cell lung cancer, non-small cell lung cancer, head and neck, esophagus, gall bladder, ovary, pancreas, stomach, cervix, thyroid, prostate, and skin, including squamous cell carcinoma;

hematopoietic tumors of lymphoid lineage, including leukemia, acute lymphocytic leukemia, acute lymphoblastic leukemia, B-cell lymphoma, T-cell lymphoma, Hodgkins lymphoma, non-Hodgkins lymphoma, hairy cell lymphoma, mantle cell lymphoma, myeloma, and Burkett's lymphoma;

hematopoietic tumors of myeloid lineage, including acute and chronic myelogenous leukemias, myelodysplastic syndrome and promyelocytic leukemia;

tumors of mesenchymal origin, including fibrosarcoma and rhabdomyosarcoma;

tumors of the central and peripheral nervous system, including astrocytoma, neuroblastoma, glioma and schwannomas; and

other tumors, including melanoma, seminoma, teratocarcinoma, osteosarcoma, xenoderoma pigmentosum, keratoctanthoma, thyroid follicular cancer and Kaposi's sarcoma.

Due to the key role of CDKs in the regulation of cellular proliferation in general, inhibitors could act as reversible cytostatic agents which may be useful in the treatment of any disease process which features abnormal cellular proliferation, e.g., benign prostate hyperplasia, familial adenomatosis polyposis, neuro-fibromatosis, atherosclerosis, pulmonary fibrosis, arthritis, psoriasis, glomerulonephritis, restenosis following angioplasty or vascular surgery, hypertrophic scar formation, inflammatory bowel disease, transplantation rejection, endotoxic shock, and fungal infections.

Compounds of the invention may also be useful in the treatment of Alzheimer's disease, as suggested by the recent finding that CDK5 is involved in the phosphorylation of tau protein (J. Biochem, (1995) 117, 741-749).

Compounds of the invention may induce or inhibit apoptosis. The apoptotic response is aberrant in a variety of human diseases. Compounds of the invention, as modulators of apoptosis, will be useful in the treatment of cancer (including but not limited to those types mentioned hereinabove), viral infections (including but not limited to herpevirus, poxvirus, Epstein-Barr virus, Sindbis virus and adenovirus), prevention of AIDS development in HIV-infected individuals, autoimmune diseases (including but not limited to systemic lupus, erythematosus, autoimmune mediated glomerulonephritis, rheumatoid arthritis, psoriasis, inflammatory bowel disease, and autoimmune diabetes mellitus), neurodegenerative disorders (including but not limited to Alzheimer's disease, AIDS-related dementia, Parkinson's disease, amyotrophic lateral sclerosis, retinitis pigmentosa, spinal muscular atrophy and cerebellar degeneration), myelodysplastic syndromes, aplastic anemia, ischemic injury associated with myocardial infarctions, stroke and reperfusion injury, arrhythmia, atherosclerosis, toxin-induced or alcohol related liver diseases, hematological diseases (including but not limited to chronic anemia and aplastic anemia), degenerative diseases of the musculoskeletal system (including but not limited to osteoporosis and arthritis) aspirin-sensitive rhinosinusitis, cystic fibrosis, multiple sclerosis, kidney diseases and cancer pain.

Compounds of the invention, as inhibitors of the CDKs, can modulate the level of cellular RNA and DNA synthesis. These agents would therefore be useful in the treatment of viral infections (including but not limited to HIV, human papilloma virus, herpesvirus, poxvirus, Epstein-Barr virus, Sindbis virus and adenovirus).

Compounds of the invention may also be useful in the chemoprevention of cancer. Chemoprevention is defined as inhibiting the development of invasive cancer by either blocking the initiating mutagenic event or by blocking the progression of pre-malignant cells that have already suffered an insult or inhibiting tumor relapse.

Compounds of the invention may also be useful in inhibiting tumor angiogenesis and metastasis.

Compounds of the invention may also act as inhibitors of other protein kinases, e.g., protein kinase C, her2, raf 1, MEK1, MAP kinase, EGF receptor, PDGF receptor, IGF receptor, PI3 kinase, weel kinase, Src, Abl and thus be effective in the treatment of diseases associated with other protein kinases.

Another aspect of this invention is a method of treating a mammal (e.g., human) having a disease or condition associated with the CDKs by administering a therapeutically effective amount of at least one compound of the invention, or a pharmaceutically acceptable salt or solvate of said compound to the mammal.

A preferred dosage is about 0.001 to 500 mg/kg of body weight/day of the compound of the invention. An especially preferred dosage is about 0.01 to 25 mg/kg of body weight/day of a compound of the invention, or a pharmaceutically acceptable salt or solvate of said compound.

The compounds of this invention may also be useful in combination (administered together or sequentially) with one or more of anti-cancer treatments such as radiation therapy, and/or one or more anti-cancer agents selected from the group consisting of cytostatic agents, cytotoxic agents (such as for example, but not limited to, DNA interactive agents (such as cisplatin or doxorubicin)); taxanes (e.g. taxotere, taxol); topoisomerase 11 inhibitors (such as etoposide); topoisomerase I inhibitors (such as irinotecan (or CPT-11), camptostar, or topotecan); tubulin interacting agents (such as paclitaxel, docetaxel or the epothilones); hormonal agents (such as tamoxifen); thymidilate synthase inhibitors (such as 5-fluorouracil); anti-metabolites (such as methoxtrexate); alkylating agents (such as temozolomide (TEMODAR™ from Schering-Plough Corporation, Kenilworth, N.J.), cyclophosphamide); Farnesyl protein transferase inhibitors (such as, SARASAR™ (4-[2-[4-[(11R)-3,10-dibromo-8-chloro-6, 11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-yl-]-1-piperidinyl]-2-oxoehtyl]-1-piperidinecarboxamide, or SCH 66336 from Schering-Plough Corporation, Kenilworth, N.J.), tipifarnib (Zarnestra® or R115777 from Janssen Pharmaceuticals), L778,123 (a farnesyl protein transferase inhibitor from Merck & Company, Whitehouse Station, N.J.), BMS 214662 (a farnesyl protein transferase inhibitor from Bristol-Myers Squibb Pharmaceuticals, Princeton, N.J.); signal transduction inhibitors (such as, Iressa (from Astra Zeneca Pharmaceuticals, England), Tarceva (EGFR kinase inhibitors), antibodies to EGFR (e.g., C225), GLEEVEC™ (C-abl kinase inhibitor from Novartis Pharmaceuticals, East Hanover, N.J.); interferons such as, for example, intron (from Schering-Plough Corporation), Peg-Intron (from Schering-Plough Corporation); hormonal therapy combinations; aromatase combinations; ara-C, adriamycin, cytoxan, Clofarabine (Clolar® from Genzyme Oncology, Cambridge, Massachusetts), cladribine (Leustat® from Janssen-Cilag Ltd.), aphidicolon, rituxan (from Genentech/Biogen Idec), sunitinib (Sutent® from Pfizer), dasatinib (or BMS-354825 from Bristol-Myers Squibb), tezacitabine (from Aventis Pharma), Sml1, fludarabine (from Trigan Oncology Associates), pentostatin (from BC Cancer Agency), triapine (from Vion Pharmaceuticals), didox (from Bioseeker Group), trimidox (from ALS Therapy Development Foundation), amidox, 3-AP (3-aminopyridine-2-carboxaldehyde thiosemicarbazone), MDL-101,731 ((E)-2′-deoxy-2′-(fluoromethylene)cytidine) and gemcitabine.

Other anti-cancer (also known as anti-neoplastic) agents include but are not limited to Uracil mustard, Chlormethine, Ifosfamide, Melphalan, Chlorambucil, Pipobroman, Triethylenemelamine, Triethylenethiophosphoramine, Busulfan, Carmustine, Lomustine, Streptozocin, Dacarbazine, Floxuridine, Cytarabine, 6-Mercaptopurine, 6-Thioguanine, Fludarabine phosphate, oxaliplatin, leucovirin, oxaliplatin (ELOXATIN™ from Sanofi-Synthelabo Pharmaeuticals, France), Pentostatine, Vinblastine, Vincristine, Vindesine, Bleomycin, Dactinomycin, Daunorubicin, Doxorubicin, Epirubicin, Idarubicin, Mithramycin, Deoxycoformycin, Mitomycin-C, L-Asparaginase, Teniposide 17α-Ethinylestradiol, Diethylstilbestroi, Testosterone, Prednisone, Fluoxymesterone, Dromostanolone propionate, Testolactone, Megestrolacetate, Methylprednisolone, Methyltestosterone, Prednisolone, Triamcinolone, Chlorotrianisene, Hydroxyprogesterone, Aminoglutethimide, Estramustine, Medroxyprogesteroneacetate, Leuprolide, Flutamide, Toremifene, goserelin, Cisplatin, Carboplatin, Hydroxyurea, Amsacrine, Procarbazine, Mitotane, Mitoxantrone, Levamisole, Navelbene, Anastrazole, Letrazole, Capecitabine, Reloxafine, Droloxafine, Hexamethylmelamine, Avastin, herceptin, Bexxar, Velcade, Zevalin, Trisenox, Xeloda, Vinorelbine, Porfimer, Erbitux, Liposomal, Thiotepa, Altretamine, Melphalan, Trastuzumab, Lerozole, Fulvestrant, Exemestane, Fulvestrant, Ifosfomide, Rituximab, C225 (or Cetuximab from Merck KGaA, Darmstadt, Germany), and Campath.

The compounds of this invention may specifically be useful in combination (administered together, concurrently or sequentially) with temozolomide and/or radiation therapy.

If formulated as a fixed dose, such combination products employ the compounds of this invention within the dosage range described herein and the other pharmaceutically active agent or treatment within its dosage range. For example, the CDC2 inhibitor olomucine has been found to act synergistically with known cytotoxic agents in inducing apoptosis (J. Cell Sci., (1995) 108, 2897. Compounds of The invention may also be administered sequentially with known anticancer or cytotoxic agents when a combination formulation is inappropriate. The invention is not limited in the sequence of administration; compounds of the invention may be administered either prior to or after administration of the known anticancer or cytotoxic agent. For example, the cytotoxic activity of the cyclin-dependent kinase inhibitor flavopiridol is affected by the sequence of administration with anticancer agents. Cancer Research, (1997) 57, 3375. Such techniques are within the skills of persons skilled in the art as well as attending physicians.

Accordingly, in an aspect, this invention includes combinations comprising an amount of at least one compound of the invention, or a pharmaceutically acceptable salt, solvate, ester or prodrug thereof, and an amount of one or more anti-cancer treatments and anti-cancer agents listed above wherein the amounts of the compound treatments result in desired therapeutic effect.

The pharmacological properties of the compounds of this invention may be confirmed by a number of pharmacological assays. The exemplified pharmacological assays which are described later have been carried out with the compounds according to the invention and their salts.

This invention is also directed to pharmaceutical compositions which comprise at least one compound of the invention, or a pharmaceutically acceptable salt, solvate, ester or prodrug of said compound and at least one pharmaceutically acceptable carrier.

For preparing pharmaceutical compositions from the compounds described by this invention, inert, pharmaceutically acceptable carriers can be either solid or liquid. Solid form preparations include powders, tablets, dispersible granules, capsules, cachets and suppositories. The powders and tablets may be comprised of from about 5 to about 95 percent active ingredient. Suitable solid carriers are known in the art, e.g., magnesium carbonate, magnesium stearate, talc, sugar or lactose. Tablets, powders, cachets and capsules can be used as solid dosage forms suitable for oral administration. Examples of pharmaceutically acceptable carriers and methods of manufacture for various compositions may be found in A. Gennaro (ed.), Remington's Pharmaceutical Sciences, 18^(th) Edition, (1990), Mack Publishing Co., Easton, Pa.

Liquid form preparations include solutions, suspensions and emulsions. As an example may be mentioned water or water-propylene glycol solutions for parenteral injection or addition of sweeteners and opacifiers for oral solutions, suspensions and emulsions. Liquid form preparations may also include solutions for intranasal administration.

Aerosol preparations suitable for inhalation may include solutions and solids in powder form, which may be in combination with a pharmaceutically acceptable carrier, such as an inert compressed gas, e.g. nitrogen.

Also included are solid form preparations that are intended to be converted, shortly before use, to liquid form preparations for either oral or parenteral administration. Such liquid forms include solutions, suspensions and emulsions.

The compounds of the invention may also be deliverable transdermally. The transdermal compositions can take the form of creams, lotions, aerosols and/or emulsions and can be included in a transdermal patch of the matrix or reservoir type as are conventional in the art for this purpose.

The compounds of this invention may also be delivered subcutaneously.

Preferably the compound is administered orally.

Preferably, the pharmaceutical preparation is in a unit dosage form. In such form, the preparation is subdivided into suitably sized unit doses containing appropriate quantities of the active component, e.g., an effective amount to achieve the desired purpose.

The quantity of active compound in a unit dose of preparation may be varied or adjusted from about 1 mg to about 100 mg, preferably from about 1 mg to about 50 mg, more preferably from about 1 mg to about 25 mg, according to the particular application.

The actual dosage employed may be varied depending upon the requirements of the patient and the severity of the condition being treated. Determination of the proper dosage regimen for a particular situation is within the skill of the art. For convenience, the total daily dosage may be divided and administered in portions during the day as required.

The amount and frequency of administration of the compounds of the invention and/or the pharmaceutically acceptable salts thereof will be regulated according to the judgment of the attending clinician considering such factors as age, condition and size of the patient as well as severity of the symptoms being treated. A typical recommended daily dosage regimen for oral administration can range from about 1 mg/day to about 500 mg/day, preferably 1 mg/day to 200 mg/day, in two to four divided doses.

Another aspect of this invention is a kit comprising a therapeutically effective amount of at least one compound of the invention, or a pharmaceutically acceptable salt, solvate, ester or prodrug of said compound and a pharmaceutically acceptable carrier, vehicle or diluent.

Yet another aspect of this invention is a kit comprising an amount of at least one compound of the invention, or a pharmaceutically acceptable salt, solvate, ester or prodrug of said compound and an amount of at least one anticancer therapy and/or anti-cancer agent listed above, wherein the amounts of the two or more ingredients result in desired therapeutic effect.

The invention disclosed herein is exemplified by the following preparations and examples which should not be construed to limit the scope of the disclosure. Alternative mechanistic pathways and analogous structures will be apparent to those skilled in the art.

Where NMR data are presented, ¹H spectra were obtained on either a Varian VXR-200 (200 MHz, ¹H), Varian Gemini-300 (300 MHz) or XL400 (400 MHz) and are reported as ppm down field from Me₄Si with number of protons, multiplicities, and coupling constants in Hertz indicated parenthetically. Where LC/MS data are presented, analyses was performed using an Applied Biosystems API-100 mass spectrometer and Shimadzu SCL-10A LC column: Altech platinum C18, 3 micron, 33 mm×7 mm ID; gradient flow: 0 min—10% CH₃CN, 5 min—95% CH₃CN, 7 min—95% CH₃CN, 7.5 min—10% CH₃CN, 9 min —stop. The retention time and observed parent ion are given.

The following solvents and reagents may be referred to by their abbreviations in parenthesis:

-   Thin layer chromatography: TLC -   dichloromethane: CH₂Cl₂ -   ethyl acetate: AcOEt or EtOAc -   methanol: MeOH -   trifluoroacetate: TFA -   triethylamine: Et₃N or TEA -   butoxycarbonyl: n-Boc or Boc -   nuclear magnetic resonance spectroscopy: NMR -   liquid chromatography mass spectrometry: LCMS -   high resolution mass spectrometry: HRMS -   milliliters: mL -   millimoles: mmol -   microliters: μl -   grams: g -   milligrams: mg -   room temperature or rt (ambient): about 25° C.

EXAMPLES Preparative Example 10-C

SOCl₂ (18.5 mL) was added slowly under N₂ to a stirred mixture of the acid (50.0 g, 218 mmol) and pyridine (44.0 mL) in anhydrous CH₂Cl₂ (60 mL). The mixture was stirred at 25° C. for 20 min, then Meldrum's acid (35.0 g, 243 mmol) and DMAP (66.6 g, 546 mmol) were added and the mixture was stirred under N₂ for 1 hr. Then Et₂O (2 L) was added, the mixture was washed with 1 M HCl (3×500 mL), brine (500 mL), and the organic layer was dried over Na₂SO₄, filtered, and the solvent was evaporated. The residue was dissolved in MeOH (580 mL), and the mixture was refluxed for 4 hr. The solvent was evaporated and the residue was purified by column chromatography on silica gel with 10:1 CH₂Cl₂/EtOAc as eluent. Pale yellow oil (26.5 g, 43%) was obtained.

Preparative Example 20-C

A mixture of the β-ketoester from Preparative Example 10-C (20.0 g, 70.1 mmol) and 3-aminopyrazole (5.40 g, 65.0 mmol) in anhydrous toluene (60 mL) was stirred and refluxed under N₂ for 24 hr. The solvent was evaporated and the residue was purified by column chromatography on silica gel with 20:1 CH₂Cl₂/MeOH as eluent. White solid (15.0 g, 73%) was obtained.

Preparative Example 30-C

A mixture of the product from Preparative Example 20-C (12.50 g, 39.3 mmol), N,N-dimethylaniline (15.5 mL), and POCl₃ (125 mL) was stirred at 25° C. for 4 days. Excess of POCl₃ was evaporated and the residue was poured into saturated aqueous NaHCO₃ (600 mL). The mixture was extracted with CH₂Cl₂ (3×200 mL), the combined extracts were dried over Na₂SO₄, filtered, and the solvent was evaporated. The residue was purified by column chromatography on silica gel with 8:1 CH₂Cl₂/EtOAc as eluent. Pale yellow wax (9.41 g, 71%) was obtained.

Preparative Example 40-C

A solution of NBS (4.03 g, 22.7 mmol) in anhydrous CH₃CN (40 mL) was added under N₂ to a stirred solution of the product from Preparative Example 30-C (7.63 g, 22.7 mmol) in anhydrous CH₃CN (60 mL) and CH₂Cl₂ (20 mL). The mixture was stirred for 2 hr, the solvents were evaporated, and the residue was purified by column chromatography on silica gel with 20:1 CH₂Cl₂/EtOAc as eluent. Pale yellow solid foam (9.20 g, 97%) was obtained.

Preparative Example 50-C

A mixture of the product from Preparative Example 40-C (8.00 g, 19.3 mmol) and NaOMe (2.16 g, 40.0 mmol) in anhydrous MeOH (100 mL) was stirred for 20 hr. CH₂Cl₂ (200 mL) was then added, the mixture was filtered through Celite, the solvent was evaporated, and the residue was purified by column chromatography on silica gel with 2:1 CH₂Cl₂/EtOAc as eluent. White solid (7.75 g, 98%) was obtained.

Preparative Example 60-C

To a mixture of Boc derivative (3.0 g, 7.3 mmol) from Preparative Example 50-C in DME/H₂O (16 mL/4 mL) was added 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2yl)-1H-pyrazole (2.8 g, 13.5 mmol) and Na₂CO₃ (3.9 g, 36.4 mmol). N₂ was bubbled thru the solution for 20 min with stirring whereupon PdCl₂(PPh₃)₂ (0.39 g, 0.47 mmol) was added. The mixture was heated to 110° C. and was stirred for 12 h. The mixture was cooled to rt, concentrated under reduced pressure and placed under high vacuum. The crude product was purified by flash chromatography using a 30:1 mixture of CH₂Cl₂/MeOH as eluent to afford 1.57 g (52% yield) as an orange/brown solid. LC-MS:=413.2 [M+H] 97% purity.

Preparative Example 70-C

To a solution of aniline (0.044 mL, 0.49 mmol) in dry DMSO (2 mL) at rt was added 60% NaH in oil (20 mg, 0.49 mmol) in one portion. The resulting mixture was stirred for 30 min at rt where upon the 7-methoxy adduct (0.10 g, 0.24 mmol) from Preparative Example 60-C was added in a single portion. The mixture was stirred for 12 h at rt, cooled to rt, and quenched with sat. aq. NH₄Cl (2 mL). The mixture was extracted with a mixture of 10% IPA/CH₂Cl₂ (3×10 ml) and the organic layers were combined. The organic layer was washed with brine (1×5 mL), dried (Na₂SO₄), filtered and concentrated under reduced pressure. The crude product was purified by preparative thin-layer chromatography (6×1000 μM plates) using a 12:1 mixture of CH₂Cl₂/MeOH as eluent to afford (60 mg, 53% yield) as a yellow semisolid. LC-MS:=474.4 [M+H] 94% purity.

Preparative ExampleS 80-C -90-C

Following the procedure set forth in Preparative Example 70-C but utilizing the commercially available heteroaryl amines (as indicated) in Table 10-C with the 7-methoxy adduct from Preparative Example 60-C, the substituted pyrazolo[1,5-a]pyrimidine adducts were prepared (Products).

TABLE 10-C Prep. 1. Yield (%) Ex. Amine Product 2. LC-MS 80-C

1. 32 2. 518.3 90-C

1. 42 2. 545.3

Preparative Example 100-C

3-Amino-4-bromopyrazole (5 g, 30.9 mmol) and 4-methoxybenzyl chloride (21 g, 134 mmol, 4.3 equiv.) were combined in anhydrous DMF (25 mL) and added dropwise to a stirred suspension of sodium hydride (60% dispersion in mineral oil, 6.25 g, 156 mmol, 5 equiv.) in anhydrous DMF (50 mL). The resulting suspension was stirred 2 days at room temperature. Water (300 mL) was added slowly and the resulting mixture was extracted with ether (4×350 mL). The organic layers were combined, washed with brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was dissolved in dichloromethane and purified by silica gel chromatography using a gradient from 10% to 20% ethyl acetate-hexanes. The product, a white solid, is obtained as a 60:40 mixture of the 1-benzylated-1H product and the 2-benzylated-2H product (14.96 g total, 93% yield).

Preparative Example 110-C

The compound from Preparative Example 100-C (10 g, 19.15 mmol) and 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (11.95 g, 57.42 mmol, 3.0 equiv.) were combined in 120 mL dimethoxyethane. 2M sodium carbonate solution (30 mL, 60 mmol, 3.1 equiv.) was added followed by tetrakis(triphenylphosphine) palladium(0) (2.36 g, 2.04 mmol, 0.11 equiv.). The mixture was stirred 16 hours at 90° C. After cooling to room temperature, water (200 mL) and brine (50 mL) were added and the mixture was extracted with ethyl acetate (2×200 mL). The extracts were combined, washed with brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was dissolved in dichloromethane and purified by silica gel chromatography using a gradient from 33% to 66% ethyl acetate-hexanes. The 1-benzylated-1H product (R_(f)=0.27 in 66% ethyl acetate-hexanes) elutes first, followed by the 2-benzylated-2H-product (R_(f)=0.19 in 66% ethyl acetate-hexanes). The product is obtained as a yellow solid (5.60 g total, 56% yield) with an isomeric ratio of 62:38.

Preparative Example 120-C

The compound from Preparative Example 110-C (4.3 g, 8.22 mmol) was dissolved in trifluoroacetic acid (70 mL) and stirred 17 hours at reflux. After cooling, the trifluoroacetic acid was removed under reduced pressure. The resulting residue was dissolved in tetrahydrofuran (100 mL), methanol (50 mL) and 4N aqueous sodium hydroxide solution (25 mL, 100 mmol, 12 equiv.). The mixture was stirred 4 hours at 70° C. then cooled to room temperature. The mixture was concentrated and the residue was suspended in brine (100 mL) and water (40 mL). This mixture was extracted with 20% isopropanol in ethyl acetate (8×100 mL). The extracts were combined, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product was dissolved in 10% methanol in dichloromethane and purified by silica gel chromatography using 10% methanol-dichloromethane followed by 10% 7N ammonia in methanol-dichloromethane. The product is obtained as a tan to brown solid (1.03 g, 77% yield).

Preparative Example 130-C

To a solution of aminopyrazole (0.74 g, 4.5 mmol) from Preparative Example 120-C in toluene (40 mL) in a pressure tube at rt was added β-keto ester (1.5 g, 5.0 mmol) from Preparative Example 1. The pressure tube was capped and heated to 110° C. and was stirred for 12 h. The mixture was cooled to rt and was concentrated under reduced pressure. The material was taken on crude to the next transformation. LC-MS: =399.2 [M+H]; 70% purity.

Preparative Example 140-C

To a solution of 7-hydroxyl adduct (1.84 g, 4.5 mmol) from Preparative Example 130-C in POCl₃ (13 mL, 0.14 mol) at rt was added N,N-dimethylaniline (2 mL, 15.8 mmol). The resulting solution was stirred at rt for 12 h (until complete by TLC) and was concentrated under reduced pressure. The crude material was cooled to 0° C. and was treated with CH₂Cl₂ (50 mL) and sat. aq. NaHCO₃ (10 mL). The layers were separated and the aqueous layer was extracted with CH₂Cl₂ (2×50 mL). The organic layers were combined, dried (Na₂SO₄), filtered, and concentrated under reduced pressure. The crude product was purified by flash chromatography using a 1:1 mixture of hexanes/CH₂Cl₂ as eluent to afford 1.4 g (96% yield) of a brown semisolid. LC-MS:=317.2 [M+H]; 95% purity.

Preparative Example 150-C

To a solution of 4-amino-N,N-dimethylbenzenesulfonamide (96 mg, 0.48 mmol) in dry DMSO (2 mL) at rt was added 60% NaH in oil (20 mg, 0.49 mmol) in one portion. The resulting mixture was stirred for 20 min at rt where upon the 7-chloro adduct (0.10 g, 0.24 mmol) from Preparative Example 140-C was added in a single portion. The mixture was stirred for 12 h at rt, cooled to rt, and quenched with sat. aq. NH₄Cl (2 mL). The mixture was extracted with a mixture of 10% IPA/CH₂Cl₂ (3×10 ml) and the organic layers were combined. The organic layer was washed with brine (1×5 mL), dried (Na₂SO₄), filtered and concentrated under reduced pressure. The crude product was diluted with water (10 mL) and the resultant solid was filtered off and washed with water (50 mL). The resultant ppt was placed under high vacuum to afford 0.13 g (98% yield) of a dark yellow solid. LC-MS:=581.3 [M+H] 90% purity.

Preparative Examples 150-C-190-C

Following the procedure set forth in Preparative Example 150-C but utilizing the commercially available heteroaryl amines (as indicated) in Table 20-C with the 7-chloro adduct from Preparative Example 140-C, the substituted pyrazolo[1,5-a]pyrimidine adducts were prepared (Products).

TABLE 20-C Prep. 1. Yield (%) Ex. Amine Product 2. LC-MS 150- C

1. 53 2. 552.3 160- C

1. 44 2. 581.5 170- C

1. 51 2. 552.5 180- C

1. 47 2. 615.5 190- C

1. 90 2. 538.3

Example 10-C

To a solution of Boc adduct (60 mg, 0.13 mmol) from Preparative Example 70-C in CH₂Cl₂ (3 mL) at rt was added was added TFA (1 mL). The resulting solution was stirred at rt for 5 h (until complete by TLC) and was concentrated under reduced pressure. The crude material was taken up in 2M NH₃ in MeOH (3 mL) and stirred for 12 h. The mixture was concentrated under reduced pressure and was purified by preparative thin-layer chromatography (4×1000 μM plates) using a 6:1 mixture of CH₂Cl₂/MeOH (7M NH₃) as eluent to afford (5 mg, 10% yield) as a yellow solid. mp 131-134° C.; LC-MS:=374.2 [M+H]>90% purity.

Examples 20-C-90-C

Following the procedure set forth in Example 10-C utilizing the appropriate Boc derivatives shown in Column 2 of Table 30-C, the final substituted pyrazolo[1,5-a]pyrimidine adducts were prepared (Products).

TABLE 30-C 1. Yield (%) 2. LC-MS Ex. Column 2 Product 3. mp (° C.) 20-C

1. 28 2. 418.2 3. 106-108 30-C

1. 98 2. 445.2 40-C

1. 91 2. 481.2 3. 168-171 50-C

1. 63 2. 452.2 3. 139-141 60-C

1. 66 2. 481.3 3. 145-148 70-C

1. 81 2. 452.2 3. 156-158 80-C

1. 47 2. 515.3 3. 167-169 90-C

1. 64 2. 440.2 3. 110-112 ASSAY:

BACULOVIRUS CONSTRUCTIONS: Cyclin E was cloned into pVL1393 (Pharmingen, La Jolla, Calif.) by PCR, with the addition of 5 histidine residues at the amino-terminal end to allow purification on nickel resin. The expressed protein was approximately 45 kDa. CDK2 was cloned into pVL1393 by PCR, with the addition of a haemaglutinin epitope tag at the carboxy-terminal end (YDVPDYAS). The expressed protein was approximately 34 kDa in size.

ENZYME PRODUCTION: Recombinant baculoviruses expressing cyclin E and CDK2 were co-infected into SF9 cells at an equal multiplicity of infection (MOl=5), for 48 hrs. Cells were harvested by centrifugation at 1000 RPM for 10 minutes, then pellets lysed on ice for 30 minutes in five times the pellet volume of lysis buffer containing 50 mM Tris pH 8.0, 150 mM NaCl, 1% NP40, 1 mM DTT and protease inhibitors (Roche Diagnostics GmbH, Mannheim, Germany). Lysates were spun down at 15000 RPM for 10 minutes and the supernatant retained. 5 ml of nickel beads (for one liter of SF9 cells) were washed three times in lysis buffer (Qiagen GmbH, Germany). Imidazole was added to the baculovirus supernatant to a final concentration of 20 mM, then incubated with the nickel beads for 45 minutes at 40° C. Proteins were eluted with lysis buffer containing 250 mM imidazole. Eluate was dialyzed overnight in 2 liters of kinase buffer containing 50 mM Tris pH 8.0, 1 mM DTT, 10 mM MgCl2, 100 μM sodium orthovanadate and 20% glycerol. Enzyme was stored in aliquots at −70° C.

IN VITRO KINASE ASSAY: Cyclin E/CDK2 kinase assays were performed in low protein binding 96-well plates (Corning Inc, Corning, N.Y.). Enzyme was diluted to a final concentration of 50 μg/ml in kinase buffer containing 50 mM Tris pH 8.0, 10 mM MgCl_(2,)1 mM DTT, and 0.1 mM sodium orthovanadate. The substrate used in these reactions was a biotinylated peptide derived from Histone H1 (from Amersham, UK). The substrate was thawed on ice and diluted to 2 μM in kinase buffer. Compounds were diluted in 10% DMSO to desirable concentrations. For each kinase reaction, 20 μl of the 50 μg/ml enzyme solution (1 μg of enzyme) and 20 μl of the 2 μM substrate solution were mixed, then combined with 10 μl of diluted compound in each well for testing. The kinase reaction was started by addition of 50 μl of 2 μM ATP and 0.1 μCi of 33P-ATP (from Amersham, UK). The reaction was allowed to run for 1 hour at room temperature. The reaction was stopped by adding 200 μl of stop buffer containing 0.1% Triton X-100, 1 mM ATP, 5 mM EDTA, and 5 mg/ml streptavidine coated SPA beads (from Amersham, UK) for 15 minutes. The SPA beads were then captured onto a 96-well GF/B filter plate (Packard/Perkin Elmer Life Sciences) using a Filtermate universal harvester (Packard/Perkin Elmer Life Sciences.). Non-specific signals were eliminated by washing the beads twice with 2M NaCl then twice with 2 M NaCl with 1% phosphoric acid. The radioactive signal was then measured using a TopCount 96 well liquid scintillation counter (from Packard/Perkin Elmer Life Sciences).

IC₅₀ DETERMINATION: Dose-response curves were plotted from inhibition data generated, each in duplicate, from 8 point serial dilutions of inhibitory compounds. Concentration of compound was plotted against % kinase activity, calculated by CPM of treated samples divided by CPM of untreated samples. To generate IC₅₀ values, the dose-response curves were then fitted to a standard sigmoidal curve and IC₅₀ values were derived by nonlinear regression analysis. The thus-obtained IC₅₀ value for an illustrative compound of the invention is shown in Table 2.

TABLE 2 Ex. CMPD IC50 (μM) 90-C

0.2

As demonstrated above by the assay value, the compounds of the present invention exhibit excellent CDK inhibitory properties.

While the present invention has been described with in conjunction with the specific embodiments set forth above, many alternatives, modifications and other variations thereof will be apparent to those of ordinary skill in the art. All such alternatives, modifications and variations are intended to fall within the spirit and scope of the present invention. 

1. A compound selected from the group consisting of the compounds of the formula:

or a pharmaceutically acceptable salt thereof.
 2. A pharmaceutical composition comprising an amount of at least one compound of claim 1, or a pharmaceutically acceptable salt thereof, in combination with at least one pharmaceutically acceptable carrier.
 3. A compound of claim 1 in isolated and purified form. 